The photographic transmission density was read on an Ansco-McBeth Model 12 densito:neter,
with a calibrated photographic density wedge used as a standard. Exposures were determined
by comparing densities of the field films with the density-versus-exposure curves for each film
emulsion calibrated on the Co™ source.
TABLF 2.1
EXPOSURE RANGES OF THE EMULSIONS
Emulsion Type
Range
-
r
Du Pont
502
510
606
0.05 to 10
1.0 te 100
10.0 to 3,000
Eastman
$01112
548-0 de
50.0 to 2,500
3,000 to 100,000
548-0 sc
5,000 to 100,000
2.2.2 Quartz-Fiber Dosimeters.
Seven ranges of quartz-fiber dosimeters, similar to the
IM-93/UD evaluated by Teapot Project 6.1.1, were used (References 16 and 17). These dosimeters had an accuracy of +10 percent of true dose for Co® gamma rays. The quartz-fiber dosimeters suffered serious errors because of rate dependence at rates higher than 10° r/hr;
however, data from the instruments used did not exhibit these errors since such rates were
avoided.
These dosimeters were calibrated with the Cosource and a correction was made on
all readings. All quartz-fiber dosimeters were continually checked for excessive leakage (>2
percentof full scale per day), and those showing excessive leakage were replaced. Table 2.2
lists the manufacturer’s numbers and ranges.
of 0 to 200 r.
Project 2.72 supplied 30 dosimeters with a range
2.2.3 Chemical Dosimeters. Chemical dosimeters furnished by the Air Force, Atomic Energy
Commission, and University of California at Los Angeles were of three main types, all based on
the same principle; to wit, acid formed from the irradiation of a chlorinated hydrocarbon is a linear function of radiation exposure throughout a broad range (25 to 100,000 r) (References 6, 18, 19,
20 and 21), These dosimeters had an accuracy of about 10 percent.
All dosimeters were of the direct-reading type, accomplished by observation of color changes
in the indicator dye. The color change in most instances was from red (pH 6.0 or above) to yelTABLE 2.2
QUARTZ-FIBER-DOSIMETER RANGES
Bendix No.
Range
r
;
‘
-
i
608
0 to 10
622
610 (IM-20/PD)
619
0 to 20
0 to 50
0 to 100
686 (IM-93/UD)
0 to 600
803
(IM-107)
low (pH 5.6 or below).
0 to 2,000
0 to 200
Since the color transition of the indicator dye was a function of exposure,
the exposure doses could be estimated by color comparison with irradiated controls.
Evaluation of overexposures (pH 5.6 or below) was determined bythe titration of the acid
formed per ml of chlorinated hydrocarbon with standardized 107? Normal NaOH.
15
The amountof